Spin-orbit driven ferromagnetism at half moiré filling in magic-angle twisted bilayer graphene

Fuente: arXiv
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Auteurs principaux: Lin, Jiang-Xiazi, Zhang, Ya-Hui, Morissette, Erin, Wang, Zhi, Liu, Song, Rhodes, Daniel, Watanabe, K., Taniguchi, T., Hone, James, Li, J. I. A.
Format: Preprint
Publié: 2021
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author Lin, Jiang-Xiazi
Zhang, Ya-Hui
Morissette, Erin
Wang, Zhi
Liu, Song
Rhodes, Daniel
Watanabe, K.
Taniguchi, T.
Hone, James
Li, J. I. A.
author_facet Lin, Jiang-Xiazi
Zhang, Ya-Hui
Morissette, Erin
Wang, Zhi
Liu, Song
Rhodes, Daniel
Watanabe, K.
Taniguchi, T.
Hone, James
Li, J. I. A.
contents Strong electron correlation and spin-orbit coupling (SOC) provide two non-trivial threads to condensed matter physics. When these two strands of physics come together, a plethora of quantum phenomena with novel topological order have been predicted to emerge in the correlated SOC regime. In this work, we examine the combined influence of electron correlation and SOC on a 2-dimensional (2D) electronic system at the atomic interface between magic-angle twisted bilayer graphene (tBLG) and a tungsten diselenide (\WSe) crystal. In such a structure, strong electron correlation within the moiré flatband stabilizes correlated insulating states at both quarter and half-filling, whereas SOC transforms these Mott-like insulators into ferromagnets, evidenced by robust anomalous Hall effect with hysteretic switching behavior. The coupling between spin and valley degrees of freedom is unambiguously demonstrated as the magnetic order is shown to be tunable with an in-plane magnetic field, or a perpendicular electric field. In addition, we examine the influence of SOC on the isospin order and stability of superconductivity. Our findings establish an efficient experimental knob to engineer topological properties of moiré bands in twisted bilayer graphene and related systems.
format Preprint
id arxiv_https___arxiv_org_abs_2102_06566
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Spin-orbit driven ferromagnetism at half moiré filling in magic-angle twisted bilayer graphene
Lin, Jiang-Xiazi
Zhang, Ya-Hui
Morissette, Erin
Wang, Zhi
Liu, Song
Rhodes, Daniel
Watanabe, K.
Taniguchi, T.
Hone, James
Li, J. I. A.
Mesoscale and Nanoscale Physics
Materials Science
Strongly Correlated Electrons
Strong electron correlation and spin-orbit coupling (SOC) provide two non-trivial threads to condensed matter physics. When these two strands of physics come together, a plethora of quantum phenomena with novel topological order have been predicted to emerge in the correlated SOC regime. In this work, we examine the combined influence of electron correlation and SOC on a 2-dimensional (2D) electronic system at the atomic interface between magic-angle twisted bilayer graphene (tBLG) and a tungsten diselenide (\WSe) crystal. In such a structure, strong electron correlation within the moiré flatband stabilizes correlated insulating states at both quarter and half-filling, whereas SOC transforms these Mott-like insulators into ferromagnets, evidenced by robust anomalous Hall effect with hysteretic switching behavior. The coupling between spin and valley degrees of freedom is unambiguously demonstrated as the magnetic order is shown to be tunable with an in-plane magnetic field, or a perpendicular electric field. In addition, we examine the influence of SOC on the isospin order and stability of superconductivity. Our findings establish an efficient experimental knob to engineer topological properties of moiré bands in twisted bilayer graphene and related systems.
title Spin-orbit driven ferromagnetism at half moiré filling in magic-angle twisted bilayer graphene
topic Mesoscale and Nanoscale Physics
Materials Science
Strongly Correlated Electrons
url https://arxiv.org/abs/2102.06566